This application claims priority from Japanese Application 2001-012,254, filed Jan. 19, 2001, the entirety of which is incorporated herein by reference.
1. Field of the Invention
This invention relates to a semiconductor light-emitting element, particularly a multilayered light-emitting element to generate and emit a white color light which is composed of plural epitaxial layers grown on a substrate.
2. Related Art Statement
Recently, an attention is paid to a blue color light-emitting element made of III-V semiconductor compounds or II-VI semiconductor compounds, and in reality, a GaN-based semiconductor light-emitting element and a ZnSe-based semiconductor light-emitting element are developed as such a blue color light-emitting element. In addition, a white color light-emitting element is also proposed by taking advantage of the blue color light-emitting element.
For example, in xe2x80x9cOptic Functional Material""s Manualxe2x80x9d, p457, June, 1997, published by Optronics Ltd., such a white color light-emitting element as composed of a GaInN-based LED including a sapphire single crystal and an active layer made of GaInN and a YAG fluorescent substance is disclosed.
Moreover, in Japanese Laid-open Patent Publication Kokai Hei 2000-49374 (JP A 2000-49374), such a white color light-emitting element as to generate and emit a white color light by superimposing a blue color light or a blue-green color light emitted from a GaInN-based active layer and a yellow color light from the fluorescent color center of a GaN substrate which is excited by the blue color light or the blue-green color light, is disclosed.
In this manner, various white color light-emitting elements using GaN-based blue color light-emitting elements are proposed, but white color light-emitting elements using ZnSe-based blue color light-emitting elements are scarcely proposed, and thus, strongly desired.
It is an object of the present invention to provide a new white color light-emitting element made of II-VI semiconductor compounds such as ZnSe-based semiconductor compounds.
For achieving the above object, this invention relates to a semiconductor light-emitting element comprising:
a substrate,
a first epitaxial layer group to emit a yellow color light which is provided on the substrate and made of II-VI semiconductor compounds, and
a second epitaxial layer group to emit a blue color light which is provided on the substrate and made of II-VI semiconductor compounds.
As mentioned above, in the present invention, on a substrate are provided and stacked a first epitaxial layer group and a second epitaxial layer group which are made of II-VI semiconductor compounds. Then, a yellow color light is generated and emitted from the first epitaxial layer group and a blue color light is generated and emitted from the second epitaxial layer group. Therefore, by superimposing the yellow color light and the blue color light, a given white color light can be obtained from the semiconductor light-emitting element entirely.
In this case, by controlling the chromaticities and the intensities of the yellow color light and the blue color light independently, various white color lights such as a warm white color light or a cold white color light can be obtained. Moreover, the brightness of the thus obtained white color light is not reduced by the combination of the yellow color light and the blue color light. As a result, a much brighter white color light can be obtained in the semiconductor light-emitting element than in a conventional one.